settings: re-use attached request global config for performance

- since we *always* generate a global config and register it into request
make use of it, and not rely on the get_all_settings heavy logic that makes
it slow to fetch because of cache checks.

Within single request we're fine to re-use it when ever request attribute is available

rhodecode/lib/base.py

@@ -288,7 +288,7 b' def attach_context_attributes(context, r'
     """
     config = request.registry.settings
 
-    rc_config = SettingsModel().get_all_settings(cache=True)
+    rc_config = SettingsModel().get_all_settings(cache=True, from_request=False)
     context.rc_config = rc_config
     context.rhodecode_version = rhodecode.__version__
     context.rhodecode_edition = config.get('rhodecode.edition')

rhodecode/model/settings.py

@@ -24,6 +24,7 b' import logging'
 from collections import namedtuple
 from functools import wraps
 import bleach
+from pyramid.threadlocal import get_current_request
 
 from rhodecode.lib import rc_cache
 from rhodecode.lib.utils2 import (
@@ -210,7 +211,21 b' class SettingsModel(BaseModel):'
         invalidation_namespace = CacheKey.SETTINGS_INVALIDATION_NAMESPACE
         CacheKey.set_invalidate(invalidation_namespace)
 
-    def get_all_settings(self, cache=False):
+    def get_all_settings(self, cache=False, from_request=True):
+        # defines if we use GLOBAL, or PER_REPO
+        repo = self._get_repo(self.repo) if self.repo else None
+        key = "settings_repo.{}".format(repo.repo_id) if repo else "settings_app"
+
+        # initially try the requests context, this is the fastest
+        # we only fetch global config
+        if from_request:
+            request = get_current_request()
+
+            if request and not repo and hasattr(request, 'call_context') and hasattr(request.call_context, 'rc_config'):
+                rc_config = request.call_context.rc_config
+                if rc_config:
+                    return rc_config
+
         region = rc_cache.get_or_create_region('sql_cache_short')
         invalidation_namespace = CacheKey.SETTINGS_INVALIDATION_NAMESPACE
 
@@ -226,9 +241,6 b' class SettingsModel(BaseModel):'
             }
             return settings
 
-        repo = self._get_repo(self.repo) if self.repo else None
-        key = "settings_repo.{}".format(repo.repo_id) if repo else "settings_app"
-
         inv_context_manager = rc_cache.InvalidationContext(
             uid='cache_settings', invalidation_namespace=invalidation_namespace)
         with inv_context_manager as invalidation_context: